The present invention relates to an ejector which draws in fluid by generating a negative pressure, and a refrigerating system provided with such an ejector.
FIG. 3 is a schematic diagram showing the configuration of a refrigerating system provided with a conventional ejector. In this refrigerating system, the condenser 1 is connected to the evaporator 2 by refrigerant pipes 3 and 7, and the refrigerant pipe 7 is also connected to the compressor 5. The refrigerant in the refrigerant pipes 3 and 7 is circulated between the condenser 1 and the evaporator 2 by the compressor 5.
In such a conventional refrigerating system, a problem may arise when a piece of the wire mesh, which is disposed in the mist tank 8, breaks off and flows out toward the ejector 10 together with lubricating oil. The piece of wire mesh may become stuck in the ejector 10 and inhibit the circulating flow of the lubricating oil.
The present invention takes into consideration the above-mentioned circumstances, and has as an object to provide a refrigerating system and an ejector which does not interfere with the flow of fluid.
In accordance with one aspect of the invention, an ejector includes a negative pressure generating passage through which fluid flows; a member having a small hole disposed in the negative pressure generating passage, the fluid flowing through the small hole of the member; a negative pressure chamber disposed downstream of the member having a small hole; and an inlet passage opening to the negative pressure chamber, wherein a filter means is disposed in the inlet passage.
According to the above ejector, solid contaminants, such as pieces of wire mesh, contained in the fluid which flows into the negative pressure chamber via the inlet passage, may be removed by the filter means.
In accordance with another aspect of the invention, the filter means is a mesh type member.
According to the above ejector, solid contaminants may be removed when the fluid passes through the mesh type member.
In accordance with another aspect, the present invention provides a refrigerating system including a lubricating oil tank; an evaporator; an equalizing pipe member which connects the lubricating oil tank to the evaporator; a mist tank connected to the equalizing pipe member, the mist tank separating lubricating oil from a fluid which flows through the equalizing pipe member; and an ejector for removing the lubricating oil, which is separated in the mist tank, from the mist tank. The ejector includes a negative pressure generating passage through which a fluid flows; a member having a small hole disposed in the negative pressure generating passage, the fluid flowing through the small hole of the member; a negative pressure chamber disposed at a downstream side of the member having a small hole; and an inlet passage opens to the negative pressure chamber, the inlet passage being communicated with the mist tank. The ejector is the same as the one mentioned above.
In the above refrigerating system, the lubricating oil separated in the mist tank flows into the ejector. Although a lubricating oil separation means, such as a wire mesh, is provided in the mist tank in order to separate the lubricating oil, solid impurities, such as wire mesh pieces, may sometimes be included in the lubricating oil from the mist tank. Such solid impurities are removed by a filter means disposed in the ejector.
In yet another aspect of the invention, in the above refrigerating system, the fluid which flows through the negative pressure generating chamber comprises lubricating oil discharged from an outlet of an oil pump.
The oil pump may be disposed in the oil tank or outside the oil tank as long as it is disposed within the passages for supplying the lubricating oil in the oil tank to the portions of the compressor which require oil supply.
In yet another aspect of the invention, the refrigerating system further includes a non-return valve provided within the passage connecting the ejector to the negative pressure chamber, the non-return valve being capable of preventing flow from the negative pressure chamber toward the filter means.
According to the above refrigerating system, it becomes possible to block the flow from the negative pressure chamber side of the ejector toward the filter means, and it becomes possible to prevent the pieces of the wire mesh caught by the filter means from flowing backward.